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THE TRIONYX SCABRA, A FRESH-WATER TORTOISE FROM SUMATRA.

ON TORTOISES. No. I. THE tortoises form a very extensive order of the class reptilia; and are too remarkable in their external characters to be confounded with any other group in nature. They may be said to be enveloped in an external skeleton, which, like solid armour, affords them security from the attacks of their enemies. This panoply, however, demands a more minute attention. Let us then examine it a little in detail. A first glance assures us that it is composed of two portions or shields, an upper, which is arched so as to present a convex surface; and an under, which is more or less flat, and which, at least in most of the order, is united at its lateral edges to the convex upper shield, leaving a large irregularly-shaped aperture at each extremity, for the passage and freedom of the head, limbs, and tail, which are found, in most terrestrial and fresh-water tortoises,

VOL III.

capable of being completely retracted and sheltered within the borders of the shields. Of these shields, the upper is termed the carapace; the lower the plastron, or breastplate. The carapace is, in truth, neither more nor less than an expansion of the ribs, (eight in number on each side,) united at their edges by a suture or seam : its middle longitudinal portion consisting of the vertebræ of the back and loins, which are consolidated together, so as to be immoveable. This may be easily understood by any one who will examine the shell of the turtle, (chelonia mydas,) whose flesh is so great an article of luxury. Internally, therefore, the carapace of the tortoise presents the appearance of simple bone; externally, it is covered with scales, or plates, or skin. If the carapace represents the dorsal vertebræ and ribs, consolidated and expanded, the breast-plate or plastron is analogous to the sternum Gr

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breast-bone; it is generally made up of Dine distinct portions united together, and covered externally like the carapace. Within these two osseous envelopes, are the remaining parts of the skeleton, the scapula, the clavicles, and the bones of the pelvis, (those of the head, neck, limbs, and tail excepted,) together with the muscles and

viscera.

Tortoises, like the mammalia, have true lungs for the respiration of atmospheric air; their lungs are, indeed, of immense volume, and extend over the greatest portion of the inner surface of the carapace, to which they are attached.

To those among the tortoises whose habits are aquatic, the situation of the lungs is of great advantage: it is a simple and efficient mode of enabling the floating animal to keep, without any exertion, its due position and balance among the rolling waves; for it is evident that the part containing voluminous lungs filled with air, must be perpetually the uppermost in the

water.

Mammalia breathe by expanding the chest, that is, by dilating the cavity occupied by the lungs, into which the air accordingly enters, in order to fill up the vacuum which would otherwise be occasioned. Now this action, as is very manifest, supposes a certain degree of mobility in the walls of the chest, or in other words, of the ribs which encircle it, and such is the case; independent of the action of the diaphragm, by which the cavity of the chest is alternately enlarged and contracted, there is an action of the ribs also, through the agency of certain muscles which raise them, while they bring them forward, and depress them, on restoring them to their former position. But the ribs of the tortoise entering into the formation of its solid shield, are fixed and immoveable; no part of the body is capable of being, expanded, neither is there any muscular diaphragm parting the chest from the abdominal cavity, by the action of which the lungs may be filled. How, then, is breathing effected? By an act much resembling deglutition or swallowing, and depending solely on the mouth and tongue. The jaws being firmly closed, the cavity of the mouth is dilated, by the drawing down of the root of the tongue, together with the bone (os hyoides) which supports it, and the air rushes into the mouth at the same time through the nostrils. The posterior aperture of the nostrils is now closed by the tongue, the root of the tongue is elevated, the cavity of the mouth is dimi

nished, and the air is forced down the trachea into the lungs. This mode of respiration, or rather this deglutition of air, is not peculiar to the tortoises; it is common also to the frog, the toad, and their congeners.

Tortoises, though possessing great strength in their jaws, are not provided with teeth. In most the jaws are clad in an envelope of horn, which renders them not unlike the beak of a bird; in some, however, the jaws are merely covered with skin.

The young are produced from eggs covered with a hard shell like those of birds, and hatched by the heat of the sun in the sand or mud where the female deposits them.

M.

The life of this race of beings is of long duration. In the library at Lambeth Palace is the shell of a tortoise brought alive there in 1623, and accidentally killed in 1730. At Fulham Palace, one procured in 1628, died in 1753. In 1813, one was living at Petersburgh, which was known to have been two hundred and twenty years old. Many similar instances are on record. A collection of them by any of our ingenious readers, would be interesting.

(To be continued.)

SCRIPTURE EXPLANATIONS.-No. XXVI. The "little cloud."-1 Kings xviii. 44. THE REV. R. Walsh, LL.D., in his narrative of a journey from Constantinople to England, remarks, that it would have been quite impossible for a large city to have existed on the spot where Constantinople is situated, if some artificial means had not been devised to supply the deficiencies of nature, as it regards water. The first of these means are cisterns and wells, constructed at the bottoms of houses, as reservoirs, to save the rain-water that falls in winter; but to a people like the Turks, to whom water is a religious as well as a natural want, and who use it for ablution as well as drinking, it was necessary to have a much more abundant supply; and this is found in the bends or tanks which they have constructed in the mountains, near the shores of the Black Sea. These mountains are the regions of streams and showers; and wherever a small rill is found running into a valley on any elevation, a mound is raised across the lower end, and the water thus obstructed is thrown back, and accumulated till it forms a large, deep, and triangular lake. This mound is

generally faced with marble, covered with sculptures of oriental device, and has a very grand and magnificent appearance. Pipes formed of tiles, moulded into tubes, convey the water along the hills; and when a valley interposes, it is crossed by an aqueduct. Some of the aqueducts are very striking and noble in perspective.

I passed the autumn of 1822 near one of the largest and most important of these reservoirs. The summer had been remarkably dry and it appeared, from a table that I kept, that it had not rained from the 4th of April to the 2nd of November, with the exception of a few passing showers. The water in the tanks or bends became low and muddy, and the Turks took the alarm. The water engineers were sent out, and I accompanied them to some of the bends; they measured the quantity of water, and they found no more than sufficient to supply the city for fifteen days! Judge of the consternation of seven hundred thousand persons suddenly deprived of an element essential not only for domestic uses, but religious also, and having no other possible mode of obtaining it. Prayer was offered up in the mosques, and the sky was anxiously watched. The immutability of things in the east, and the illustrations given to the writings of former times, is not the least pleasure a person experiences in these countries. The approach of rain is always indicated here as it was in Syria, by the appearance of a small, dark, dense, circumscribed cloud, hanging over either the Euxine or Propontis. A dervish stands on the top of the giant's mountain; and when he sees a cloud, he announces its approach, like Elijah from the top of Carmel. I one day climbed to the same place, and saw the dervish on the watch, and "I looked towards the sea, and beheld a little cloud rising out of the sea, like a man's hand, and gat me down that the rain stopped me not." In effect, it immediately followed, and the Turks were relieved from a very serious cause of anxiety.

THE ENERGY OF A MOTHER.

ONE of the small islands in Boston Bay was inhabited by a single poor family. The father was taken suddenly ill. There was, of course, no medical aid to be obtained. The wife, on whom every labour for the household devolved, was sleepless in care and tenderness by the bedside of her suffering husband. Every remedy in her power to procure, was ad

ministered, but the disease was acute, and he died. Seven young children mourned around the lifeless corpse. They were the sole beings upon the desolate spot. Did the mother indulge the grief of her spirit, and sit down in despair? No. She entered upon the arduous and sacred duties of her station. She felt that there was no hand to assist her in burying her dead. Providing as far as possible for the comfort of her little ones, she put her babe into the arms of the oldest, and charged the two next in age to watch the corpse of their father. She unmoored her husband's fishing-boat, which but two days before he had guided over the sea to obtain food for his family. She dared not yield to those tender recollections that might have unnerved her arm. The nearest island was at the distance of three miles. Strong winds lashed the waters to foam. Over the loud billows, that wearied and sorrowful woman rowed, and was preserved. She reached the next island, and obtained necessary aid. With such energy did her duty to her desolate babes inspire her, that the voyage which depended on her individual effort, was performed in a shorter time than the returning one, when the oars were managed by two men, who went in to assist in the last offices to the dead."

THE BENEFITS OF THE SABBATH.

THE institution of the sabbath may be esteemed one of the greatest blessings conferred upon man.

This day is Divine in its origin, inasmuch as it was ordained by God. It is likewise holy in its nature, as it was sanctified or made holy by God, Genesis ii. 3. It is also holy in its designs, as it was a day appointed by God to be separated from others for holy service; a day in which man should go up to his sanctuary, and there render acceptable service to him, and where he might receive such supplies as were every way calculated to preserve him amid the manifold temptations to which he is exposed.

It was also designed as a day of rest from the cares and turmoils of human life, and in which man should leave the engagements of this lower world, and seek those more sacred employments in which the holy soul delights.

To the christian this is a day of peculiar enjoyment, after the toilsome engagements of the week; and especially if he has been

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assailed by tormenting perplexities, by persecution, or other calamities to which his soul is subject how joyfully would he hail the return of the sabbath as a day of spiritual rest, in which he could (being released from the toils of time) rise upon the wings of faith, and catch a glimpse of that world, whither his soul is longing to take its flight, and with whose inhabitants he would delight to mingle, and to dwell in paradise for ever beneath the smiles of a reconciled God. H. J. T.

BOTANY.-No. VII.

ERICE.

THIS order takes its type and exemplar from the heaths, which are old acquaint- | ances of every one who has taken an excursion upon any of our heaths, commons, and other open grounds. There is a very beautiful characteristic of this order, which the lover of plants will be delighted in finding, if he examines the anthers, or those little heads, which our forefathers called aglets. The distinction consists, in the first place, in the presence of two threadlike appendages hanging from the lower part of the

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anthers, as shown in figure a, which bits a back view of the anther.

what has just been said about the peculiar structure of the anthers, while the result of the examination, especially if the eye be assisted by a magnifier of small power, will fairly recompense the collector's curiosity and trouble. The seed-vessel, figure e, of the erica, affords another mark for discrimination; it is superior, that is to say, above the calyx, within the hollow of which it is found. The valves, or folding pieces that compose the walls or sides of the seed-vessel, are either four or five in number; from the middle line of each, a partition, which reaches to the central column, is seen to originate. These partitions are represented in figure d of the preceding cut. The union of two valves is shown by the front descending line; at this line the valves part, and give exit to the minute seeds. The little fan-shaped processes, drawn in the void spaces, represent the seeds resting in four bundles upon their four collective bases. The corolla consists of four or five petals, more frequently adhering by their edges, and forming a tube or urn-shaped cup. The calyx is not in distinct leaves, but generally divided into four or five deep segments. There is often a beautiful harmony in the number of members which compose each separate portion of a flower. In the heath we have, for example, four segments of the calyx, four segments of the corolla, and twice four, or eight stamens. In the andromeda, or wild rosemary, we have five parts in the calyx, five teeth in the edge of the corolla, and twice five, or ten stamens. In the same plant we find also five cells in the seedvessel, as in the heath we have four cells to correspond with the fours in the rest of the parts.

EXAMPLES

Erica. The divisons of the calyx so exhi-detached from each other that they may be said to be leaves rather than segments. These are four in number. Corolla four cleft; filaments originating from the receptacle or base of the flower, and not from the corolla; anthers with an opening at the top, as we have described them, with a pair of appendages at the base; seedvessels with four cells or compartments.

Anthers generally consist of two cells; and here we see that the cells or little pouches are peculiarly distinct from each other. The second point of distinction is in the manner in which these anthers shed their pollen, namely, by two little pores or openings at the top, as is represented in figure b. Figure c represents the common, or, to speak more properly, the general form of an anther; the black descending line that divides each cell, denotes the more frequent manner of bursting, in order that the pollen may be shed. The common heath, which may be met with in all places where the soil is sandy and barten, will afford a specimen to exemplify

E. vulgaris, common heath or ling.Corolla, bell-shaped, with a double calyx ; leaves opposite, in pairs, and shaped like an arrow-head at their base. The beautiful little appendages are distinguished by an appropriate name, aures; if examined through a glass, will be found to have their edges finely toothed, like the edge of a saw.

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E. tetralix, cross-leaved heath. The leaves, instead of being in pairs, as in the preceding species, are collected into warps or fours; whence the specific name tetralix, which implies a whorl of four leaves, or a coil of four turns; common on moist heaths.

E. cinerea, fine-leaved heath.-Leaves in leashes or threes, smooth, with their edges entire. The flowers are in umbels; as in the tetralix, or last species. If the calyx be closely examined, the edges of the segments will be seen to be finely sawed. The teeth upon the auris are more distinct than they are in the common heath.

By way of embellishment as well as instruction, we will give cuts of two foreign species of ericæ.

E. empetrifalice, crowberry-leaved heath. -Corolla rough, pitcher or urn-shaped ; border bent back and spreading. Stigma appearing beyond the corolla. This species was first found by Masson, growing spontaneously, near Bay Falls.

number five instead of four. For in this genus, the calyx is parted into five divisions; the egg-shaped corolla has its mouth with five clefts; and the stamens are ten or twice five in number. The capsule also has five cells; but the anthers are provided with aures, as in the heath.

A. Polifolia, wild rosemary.-Peduncles, or flowering stalks, growing in a close bundle; leaves alternate and not in pairs, threes, or fours, as in the heaths; they are lance-shaped and rolled back upon themselves; found on turf bogs.

There is a remarkable fact connected with the history of these two genera, ericæ and andromeda. The erica numbers more than two hundred species, but they are all confined to the old continent, so that when we find a heath-like plant upon the northern parts of the new continent of America, we may be assured, without examination, that it is not an erica, but generally a species of andromeda.

Arbutus-Calyx five parted, corolla egg-shaped, with the mouth five cleft, as in the andromeda. If it be held up between the light and the eye, the base will be perceived to be pellucid; the germen, instead of turning into a dry ripened capsule, becomes a soft, pulpy berry, with five cells.

A. unedo, common strawberry-tree.Stem rising to the consideration of a tree; leaves smooth; flowers in a loose cluster, or panicle, terminating the branch: Grows in the West of Ireland. A. uva ursi, bear-berries. Stems procumbent or resting on the ground; leaves smooth, with their edges entire, veined like net-work underneath. Found on heaths.

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OLD HUMPHREY ON CONSISTENCY.

THERE is a term used among artists called keeping, which means that the tone and effect of the different parts of a picture should be in agreement with the whole; now, keeping is quite as necessary in passing through life, as in painting a picture.

A man who wears a ring and a gold chain should not be out at the elbows. Nor would it look well to see a minister of the gospel dressed in a soldier's uniform; these things would be out of order, out of propriety, out of keeping; there would be no consistency in them.

But there is a keeping, a consistency in things as well as in persons, in books as well as in men. I was led into this train of thinking by taking up a religious magazine the other day, whose outside cover and

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